There are a variety of conventional air pump pistons capable of inflating an object in a dual-directional manner. The air pump piston disclosed in the U.S. Pat. No. 5,051,073 is a case in point. These conventional air pump pistons are generally different in construction from one another and are similar in operating principle. The air pump piston of the prior art is fitted snugly into an air pump cylinder such that the cylinder is divided into two compression chambers. The piston is forced back and forth within the cylinder such that the air in the first compression chamber is compressed by the piston in a forward stroke, and that the air in the second compression chamber is compressed by the piston in a return stroke. The compressed air in the first and the second compression chambers is guided respectively into a hollow piston rod via the radially disposed air holes of the piston before the compressed air is transmitted to the air pump head through which the compressed air is forced into a tire via the inflation valve of the tire, which is engaged with the air pump head.